White class gap in math test scores as great now as black-white gap in the racial backwater prior to Brown vs. Board of Ed.

One thing that the story didn’t point out is that the class gaps even just within non-Hispanic whites are growing and this also exceeds the black-white test score gap. I’ve appended a chart showing the within whites 90/10 math scores over time [comparing the math scores of a white child in a family earning $160,000 to the math scores over time of a white child in a family earning $17,500 in 2008]. [This is from an Appendix to Sean Reardon’s paper, Figure 5.A2.]

The first graph shows that by 2000, the within white class gap (90/10) ratio has now risen to almost 1.25. It started rising with the birth cohort born around 1972, or in other words high school seniors around 1990. This white class gap has risen about 65% from 0.75 in the early 1970s to almost 1.25 by 2000. Reardon notes that 1.0 on this scale is about the difference in math between a 5th grader and an 8th grader. So the white class gap is probably nearing the difference between an average 5th grader and a 9th grader. [Interestingly, the white class gaps for math are greater than the class gaps within Blacks or Hispanics, probably because the wealth gap between the 90th and 10th percentiles for whites are wider than the similar wealth gap among Hispanics or Blacks.]

The second graph solid line shows whites and non-whites together but the dotted line on the second chart (the black-white racial gap) has been almost halved over the last 60 years from about 1.2, dropping to around 0.65 by 2000 (about the difference between a 5th grader and a 7th grader).

So even if you take race completely out of the equation, the class gap in math (and reading scores) within whites is almost DOUBLE the racial gap along these same measures and upper class whites are about 2 grade levels ahead compared to the black-white gap. And the within white class gap in math test scores is about as great as the black-white test score gap in math was in the racial backwater leading up to Brown vs. Board of Education when the Supreme Court recognized that racially separate schools were inherently unequal.

See somewhat related strong Op-Ed by Nick Kristof “The White Underclass” (2/9/12) (acknowledging some of the social truth of the cultural and family collapse of the white working class as Charles Murray’s Coming Apart does, while also identifying the much larger structural changes taking place as well which Murray does not).